Vent cap for battery

ABSTRACT

The present invention relates to a storage-battery vent cap which adjusts an internal pressure of a storage battery by exhausting a gas generated inside the storage battery to the outside and blocking inflow of external air. The vent cap includes a cylindrical body installed in a vent hole of the battery and formed with an exhaust hole; a cylindrical insert coupled to the body, a partition being formed inside the insert and a coupling hole and a air vent being formed in the partition; and a valve fixed to the coupling hole and elastically deformed by an internal pressure of the battery to open the air vent. The valve has an umbrella-like shape including a valve body having a larger diameter than that of the coupling hole, a cover formed on an outer circumferential surface of the valve body, and a fixing portion downwardly protruded from the valve body.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2012-0130323 filed in the Korean IntellectualProperty Office on Nov. 16, 2012, the entire contents of which areincorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to a vent cap for a storage battery, andin particular, it relates to a vent cap for a storage battery (orreferred to as a storage-battery vent cap), which adjusts an internalpressure of the storage battery by exhausting a gas generated inside thestorage battery to the outside and blocking inflow of external air.

2. Description of the Related Art

A lead storage battery is a rechargeable battery which can be repeatedlycharged and discharged by an oxidation-reduction reaction generatedbetween sulfuric acid serving as electrolyte and two plates formed oflead and lead oxide. The lead storage battery typically includes aplurality of plates (positive plates and negative plates) which arealternatively arranged and separators for separating the adjacentplates, and sulfuric acid serving as electrolyte solution is filled inspaces other than the plates and the separators.

The lead storage battery has high reliability and stability satisfyingmany characteristics required as the rechargeable battery since it hasdeveloped for a long period of time. Further, the lead storage batteryshows systematized high technical completeness and has been applied tovarious fields at a low cost.

However, since water of the electrolyte solution is decomposeddeteriorating performance of the battery, the lead storage battery needsperiodic water supplement, which is a troublesome job. As one of themethods for solving such a problem, a study on a technique for sealingthe lead storage battery has been developed.

A valve regulated lead acid (VRLA) storage battery is one of suchsealing-type lead storage batteries. The VRLA storage battery has designdifferences in applications of a special separator, called as anabsorbent glass mat (AGM) having an absorption function of theelectrolyte solution, high-compression of plates, and low resistance.The VRLA storage battery also has an operational difference in thathydrogen gas and oxygen gas generated by the water decomposition of theelectrolyte solution when overcharged are reduced and returned to theinside thereof through a gas-recombination operation.

As in the VRLA storage battery, when a sealed lead storage battery isovercharged, electrolyte solution is electrolyzed so as to generatehydrogen gas and oxygen gas, thereby increasing an internal pressure ofthe battery. This increase of pressure caused by the generated gases notonly deteriorates performance of the battery but also involves the riskof exploding a case of the battery. Accordingly, means for exhausting agas generated inside the storage battery to the outside and blockinginflow of external air should be developed.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a storage-battery ventcap, capable of improving cycle-life of a storage battery by blockingleakage of electrolyte solution, quickly exhausting a gas, and operatinga valve at an appropriate range of pressure.

Another object of the present invention is to provide a storage-batteryvent cap, having a simple structure and a strong coupling strength ofconstituent elements, and being capable of simplifying a manufacturingprocess.

In accordance with an aspect of the present invention, there is provideda storage-battery vent cap includes: a cylindrical body installed in avent hole of a storage battery and formed with an exhaust hole; acylindrical insert coupled to the body, a partition being formed insidethe insert and a coupling hole and a air vent being formed in thepartition; and a valve fixed to the coupling hole and elasticallydeformed by an internal pressure of the storage battery to open the airvent.

The valve may have an umbrella-like shape including a valve body havinga larger diameter than that of the coupling hole, a cover formed on anouter circumferential surface of the valve body, and a fixing portiondownwardly protruded from the valve body. The valve body and the fixingportion may be respectively adhered to a top surface and a bottomsurface of the partition to fix the valve to the insert. When aninternal pressure of the storage battery is increased, the cover may beelastically deformed to open the air vent.

The coupling hole may be formed at a center of the partition, and theair vent may be formed around the coupling hole. The air vent mayinclude a plurality of air vents radially disposed about the couplinghole, and the air vent may have a slit shape extending in acircumferential direction about the coupling hole.

The body may have a cylindrical shape having a sealed upper end, theexhaust hole may be formed on a side surface of the body, and a couplinggroove is formed an outer circumference of the body.

The insert may be inserted through an open lower end of the body, aflange may be formed on a lower outer circumferential surface of theinsert, and a coupling protrusion to be inserted into the couplinggroove may be formed on the outer circumferential surface of the insert.

A packing may be interposed between a lower end of the body and theflange, and the packing may be compressed when the body and the insertis coupled to each other. A mounting groove into which a part of thepacking is to be inserted may be formed on a top surface of the flange,and the mounting groove may have a shape of which depth gets deepertoward the inside. An installing groove may be formed at an upper endand a middle end of the body, and an O-ring is inserted into theinstalling groove.

In accordance with the aforementioned structure of the present aspect,the valve is elastically deformed according to the internal pressure ofthe storage battery to open or close the air vent. Accordingly, it ispossible to prevent leakage of electrolyte solution in a normal state byusing the vent cap. Further, by operating the valve according to theinternal pressure of the storage battery, a gas can be exhausted toimprove cycle-life of the storage battery.

Furthermore, in the present exemplary embodiment, the open bottomsurface of the insert is connected to the inside of the storage battery.Accordingly, the valve can be reliably operated in an appropriate levelof pressure. Particularly, since the cover formed on the outercircumferential surface of the valve body is elastically deformable, itis possible to quickly exhaust the gas and reliably block inflow ofexternal air.

Moreover, in the present exemplary embodiment, since the vent cap has asimple structure including the body, the insert, and the valve, it ispossible to obtain has a small possibility of breakdown and a reliableoperation, and reduce a production cost. In addition, since the body andthe insert are coupled to each other through the coupling groove and thecoupling protrusion and the insert and the valve are coupled to eachother through the coupling hole and the fixing protrusion, it ispossible to easily assemble constituent elements and obtain strongcoupling strength of the constituent elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a storage-battery vent cap inaccordance with an exemplary embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the vent cap inaccordance with the present exemplary embodiment.

FIG. 3 is a partially cut-away perspective view showing an insert of thevent cap in accordance with the present exemplary embodiment.

FIG. 4 is a cross-sectional view showing the vent cap in accordance withthe present exemplary embodiment.

FIG. 5 shows an operational state of the vent cap in accordance with thepresent exemplary embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment of the present invention will be described indetail with reference to the accompanying drawings. In assigningreference numerals to respective constituent elements in the drawings,the same reference numerals designate the same constituent elementsalthough the constituent elements are shown in different drawings.

In accordance with an exemplary embodiment of the present invention, astorage-battery vent cap (hereinafter, simply referred to as vent cap) 1is a device installed in a vent hole 510 of a storage battery 500 toadjust an internal pressure of the storage battery 500 by exhausting agas generated inside the storage battery 500 and by blocking inflow ofexternal air (see FIG. 5)

As shown in FIG. 1 and FIG. 2, the vent cap 1 includes a body 100, aninsert 200 installed inside the body 100, and a valve 300 fixed to theinsert 200. The vent cap 1 having such a structure has a smallpossibility of breakdown and a reliable operation since the structurethereof is simple. Further, the vent cap 1 is easy to manufacture andassemble, thereby reducing a production cost thereof.

Constituent elements 100 to 300 of the vent cap 1 having theaforementioned objects and effects will be described below.

Referring to FIG. 2 and FIG. 4, the body 100 is formed to have a hollowcylindrical shape with a circular cross section. An upper portion of thebody 100 is sealed, and a flange 110 is provided at the circumference ofa sealed upper end of the body 100.

The flange 110 serves as a stopper for preventing the vent cap 1 frombeing inserted over a predetermined depth when the vent cap 1 isinstalled in the vent hole 510 of the storage battery 500 (see FIG. 5).The flange 110 is formed of a circular plate having a predeterminedthickness and has a greater diameter than that of the body 100. A toolgroove 112 is formed on a top surface of the flange 110 to install thevent cap 1 in the storage battery 500 or disconnect the vent cap 1 fromthe storage battery 500 by using a predetermined tool.

Except for the flange 110, the body 100 is formed to have a multi-stepspool shape with large diameter portions 122 and 124 and small diameterportions 132 and 134. The large diameter portions 122 and 124 arerespectively located at an upper end and a middle end of the body 100,and the small diameter portions 132 and 134 are respectively locatedbetween the pair of large diameter portions 122 and 124 and at a lowerend of the body 100.

The large diameter portions 122 and 124 are adhered to an innercircumferential surface of the vent hole 510 when the vent cap 1 isinstalled. Installing grooves 126 and 128 are respectively formed at thepair of large diameter portions 122 and 124, and O-rings 410 and 420 arerespectively inserted into the mounting grooves 126 and 128. A malescrew 129 is formed on an outer circumferential surface of the largediameter portion 124 located at the middle end of the body 100. In thiscase, the O-rings 410 and 420 serve to seal a space between the body 100and the vent hole 510 to thereby prevent exhaust of an internal gas andinflow of external air when the vent cap 1 is installed. The male screw129 engages with a female screw 512 formed in the vent hole 510 tofacilitate screw-connection when the vent cap is installed.

An exhaust hole 136 connected to the inside of the body 100 is formed inthe small diameter portion 132 (located at an upper side) of the pair ofthe small diameter portions 132 and 134. When the vent cap 1 isinstalled, the small diameter portion 132 in which the exhaust hole 136is installed is located to correspond to a discharge hole 520 of thestorage battery 500 (see FIG. 5). Accordingly, a gas exhausted throughthe exhaust hole 136 is exhausted to the outside through the dischargehole 520.

As shown in FIG. 4, a coupling groove 140 is formed at a lower innercircumference of the body 100. In cooperation with a coupling protrusion250 to be described later, the coupling groove 140 serves to connect thebody 100 with the insert 200. By using the coupling groove 140 and thecoupling protrusion 250, the body 100 and the insert 200 can be coupledto each other in a one-touch method in such a way so as to facilitateeasy coupling but difficult disconnection.

As shown in FIG. 2 to FIG. 4, the insert 200 is formed to have a hollowcylindrical shape with a circular cross section. The insert 200 has atop end and a bottom end which are open, and a partition 210 is formedat a middle inner circumferential surface to divide an inner space ofthe insert 200 into two spaces. In the partition 210, a coupling hole220 at which a valve 300 is installed and an air vent 230 through whicha gas generated inside the storage battery 500 passes are formed. Thecoupling hole 220 is formed at a center of the partition 210, and theair vent 230 is formed around the coupling hole 220. For example, in thepresent exemplary embodiment, three air vents 230 are radially formedand disposed about the coupling hole 220. The air vent 230 has a slitshape extending in a circumferential direction about the coupling hole220.

For the shape of the insert 200 described above, since the bottom end ofthe insert 200 has a completely open shape, the internal pressure of theinsert 200 is maintained to be the same as that of the storage battery500. In other words, when the internal pressure of the storage battery500 is raised due to the gas generated inside the storage battery 500and reaches a predetermined level, the internal pressure of the insert200 is also increased identically to that of the storage battery 500. Asa result, the valve 300 is reliably operated according to the internalpressure of the storage battery 500 to thereby quickly exhaust the gasand efficiently block inflow of external air.

A flange 240 is formed on a lower outer circumferential surface of theinsert 200, and a packing 430 is interposed between a lower end of thebody 100 and the flange 240. The packing 430 serves to prevent leakageof gas into a gap between the body 100 and the insert 200 and to blockinflow of external air. When the insert 200 is coupled to the body 100,the packing 430 is compressed by the lower end of the insert 200 and theflange 240 to completely seal the gap between the body 100 and theinsert 200. In this case, a mounting groove 260 into which a part of thepacking 430 is to be inserted is formed on a top surface of the flange240. The mounting groove 260 is formed to have a deeper depth toward theinside so as to prevent dislocation of the packing 430 when it iscompressed.

The O-rings 410 and 420 are respectively injection-molded in theinstalling grooves 126 and 128, and the packing 430 is injection-moldedat the lower end of the body 100. The O-rings 410 and the 420 and thepacking 430 are connected to each other through a runner which isinjection-molded at a groove formed at a side of the body 100.

A coupling protrusion 250 is formed at an upper portion of the flange240 in the lower outer circumferential surface of the insert 200. Incooperation with the coupling groove 140, the coupling protrusion 250serves to couple the body 100 to the insert 200. When the couplinggroove 140 and the coupling protrusion 250 are used, the body 100 andthe insert 200 can be coupled to each other in the one-touch method.This is because the upper portion of the coupling protrusion 250 has ataper shape which gets thinner toward the upper direction. In otherwords, the coupling protrusion 250 has a narrowed upper portion and awidened lower portion. Accordingly, it is possible to easily insert theinsert 200 into the body 100 in a forwarding direction. However, sincethe widened lower portion of the coupling protrusion 250 is insertedinto the coupling groove 140 and hooked by the coupling groove 140 in anbackward direction, it is not easy to disconnect the insert 200 from thebody 100. As a result, in the present exemplary embodiment, the vent cap1 has some advantages in that it is easy to assemble the body 100 andthe insert 200, while it is difficult to disconnect the constituentelements from each other because of strong coupling strength of theconstituent elements.

The valve 300 has an umbrella-like shape and includes a valve body 310,a cover 320 formed on an outer circumferential surface of the valve body310, and a fixing portion 330 protruded from a lower surface of thevalve body 310. This valve 300 is made of a material havingpredetermined elasticity and serves to close the air vent 230 in anormal state and to open the air vent 230 when the internal pressure ofthe storage battery 500 is increased.

The valve 300 will be described in more detail with reference to FIG. 2and FIG. 4. The valve body 310 of the valve 300 is formed of a circularplate having a diameter which is larger than that of the coupling hole220. The cover 320 is formed to have a conical-hat shape which isunfolded downwardly from an upper outer circumferential surface of thevalve body 310. A lower end of the cover 320 is formed to have adiameter in such a way so as to cover all the air vents 230 formed at acircumference of the coupling hole 220

The fixing portion 330 includes a fixing pin 332 protruded from a bottomsurface of the valve body 310 and a fixing protrusion 334 formed in amiddle end of the fixing pin 332.

In the valve 300 having the aforementioned structure and installed intothe coupling hole 220, the valve body 310 and the fixing protrusion 334are respectively adhered to a top surface and a bottom surface of thepartition 210. As a result, since the valve body 310 and the fixingprotrusion 334 have diameters which are larger than that of the couplinghole 220, the valve 300 can be reliably fixed to the partition 210

Particularly, the valve 300 is made of an elastic material. Accordingly,when the fixing pin 332 inserted into the coupling hole 220 is pulled,the diameter of the fixing protrusion 334 is reduced. This can make iteasy to install the valve 300.

The vent cap 1 having the aforementioned structure is not operated whenthe internal pressure of the storage battery 500 is equal to or smallerthan an appropriate level (e.g., 7 kPa). That is, the cover 320 of thevalve 300 is adhered to the top surface of the partition 210 so as toclose the air vent 230 as shown in FIG. 4. Accordingly, the gasgenerated inside the storage battery 500 is not exhausted to theoutside, and inflow of external air is blocked.

In contrast, when electrolyte solution is electrolyzed to generatehydrogen gas and oxygen gas, and thus the internal pressure of thestorage battery 500 is increased and exceeds the appropriate level,e.g., 7 kPa, the cover 320 adhered to the top surface of the partition210 is upwardly moved (elastically deformed) to open the air vent 230.Accordingly, the gas that is inside the storage battery 500 is exhaustedto the outside so as to adjust the internal pressure of the storagebattery 500 (see FIG. 5). In this case, the appropriate pressure atwhich the air vent 230 is opened by moving upwardly the cover 320preferably ranges from 7 to 18 kPa.

The drawings and detailed description are only examples of the presentinvention, serve only for describing the present invention and by nomeans limit or restrict the spirit and scope of the present invention.Thus, any person of ordinary skill in the art shall understand that alarge number of permutations and other equivalent embodiments arepossible. Accordingly, it will be appreciated by any person of ordinaryskill in the art that a large number of modifications, permutations andadditions are possible within the principles and spirit of theinvention, the scope of which shall be defined by the appended claimsand their equivalents.

What is claimed is:
 1. A storage-battery vent cap comprising: acylindrical body installed in a vent hole of a storage battery andformed with an exhaust hole; a cylindrical insert coupled to the body, apartition being formed inside the insert and a coupling hole and an airvent being formed in the partition; and a valve fixed to the couplinghole and elastically deformed by an internal pressure of the storagebattery to open the air vent; wherein the body has a cylindrical shapehaving a sealed upper end, and the exhaust hole is formed on a sidesurface of the body, and the insert is inserted through an open lowerend of the body, and a flange is formed on a lower outer circumferentialsurface of the insert; wherein a coupling protrusion is formed on theouter circumferential surface of the insert, and a coupling groove intowhich the coupling protrusion is to be inserted is formed an outercircumference of the body; and wherein a packing is interposed between alower end of the body and the flange, and the packing is compressed whenthe body and the insert are coupled to each other.
 2. The vent cap ofclaim 1, wherein the valve has an umbrella-like shape formed with acover formed on an outer circumferential surface thereof, and the coveris elastically deformed according to the internal pressure of the coverto open the air vent.
 3. The vent cap of claim 2, wherein the valve hasa diameter which is larger than that of the coupling hole and includes avalve body having an outer circumferential surface on which the cover isformed and a fixing portion downwardly protruded from the valve body,and the valve body and the fixing portion are respectively adhered to atop surface and a bottom surface of the partition to fix the valve tothe insert.
 4. The vent cap of claim 3, wherein the fixing portionincludes a fixing pin protruded from the valve body to extend throughthe coupling hole and a fixing protrusion formed in the fixing pin, andthe valve body and the fixing protrusion are respectively adhered to thetop surface and the bottom surface of the partition to fix the valve tothe insert.
 5. The vent cap of claim 1, wherein the coupling hole isformed at a center of the partition, and the air vent is formed aroundthe coupling hole.
 6. The vent cap of claim 5, wherein the air ventincludes a plurality of air vents radially disposed about the couplinghole.
 7. The vent cap of claim 6, wherein the air vent is a slitextending in a circumferential direction about the coupling hole.
 8. Thevent cap of claim 1, wherein a mounting groove into which a part of thepacking is to be inserted is formed on a top surface of the flange, andthe mounting groove has a shape of which depth gets deeper toward theinside.
 9. The vent cap of claim 8, wherein an installing groove isformed at an upper end and a middle end of the body, and an O-ring isinserted into the installing groove.